Lung

The lung is the essential organ of respiration in air-breathing vertebrates.

Evolutionary origins

The lungs of vertebrates are closely related (i.e. homologous) to the gas bladders of fish (but not to their gills). The evolutionary origin of both are thought to be outpocketings of the upper intestines. This is reflected by the fact that the lungs of a fetus also develop from an outpocketing of the upper intestines (see ontogeny and phylogeny). The article on swim bladders contains further details about the evolutionary origin of these two organs.

Related Topics:
Vertebrate - Homologous - Gas bladder - Fish - Gill - Fetus - Ontogeny and phylogeny - Swim bladder

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